1. Field of the Invention
The present invention relates to an apparatus and method for resolving database update coherency issues in multi-channel systems and, more particularly, to an apparatus and method for resolving security association database update coherency issues in high-speed systems having multiple security channels.
2. Description of Related Art
Data that is transferred over an interconnected computer network, such as the Internet, is susceptible to various forms of attack. These attacks may result in such things as loss of privacy, loss of data integrity, identity theft, denial of service, or any combination of these attacks. The ever-expanding popularity of the Internet for secure communications, e-commerce, and various other transactions, has led to the need to ensure communications over non-secure interconnected computer networks like the Internet are secure from such attacks.
In order to address the above-mentioned concerns, the so-called “Internet Engineering Task Force” (IETF) developed a framework of open standards for ensuring the confidentiality, integrity, and authenticity of private communications over the Internet. This standards framework is known in the art as the Internet Security Protocol, or “IPSec.” IPSec provides security services at the IP layer of a system, and allows a system to select required security protocols, determine the algorithm(s) used to secure data, and implement any cryptographic keys required to provide the security services. Because these security services are implemented within the IP layer, the IPSec services may be used by any higher layer protocol, such as TCP (Transmission Control Protocol), UDP (User Datagram Protocol), ICMP (Internet Control Message Protocol), BGP (Border Gateway Protocol), or various other protocols known in the art. IPSec can be used to establish one or more secure communication channels between host computers, between security gateways, such as a router or firewall, or between hosts and security gateways.
As is known, IP data traverses an interconnected computer network as discrete data packets, colloquially referred to as IP datagrams. IPSec provides a new set of IPSec headers that are added to IP datagrams. The new IPSec headers, among other things, provide information regarding the security protocols that are used to secure the IP datagram payload as it traverses an interconnected computer network. These security protocols are known as the Authentication Header (AH) and Encapsulating Security Payload (ESP). The AH security protocol provides connectionless integrity, data origin authentication, and an optional anti-replay service, and is represented using protocol number 51. The ESP security protocol provides confidentiality, integrity, data origin authentication, and anti-replay services, and is represented using protocol number 50. The AH and ESP protocols can be used independently or in combination with each other to provide a desired set of security services.
Fundamental to the use and understanding of IPSec is the Security Association (SA). In general, an SA is a relationship between two or more devices that describe how the devices will use IPSec's security services to securely communicate with each other. An SA is unidirectional. Hence, to secure bi-directional communication channels between two nodes in an interconnected computer network, two SAs are required, one for each direction. These individual secure communication channels are referred to as an “inbound tunnel” and an “outbound tunnel,” where one device's inbound tunnel is the other device's outbound tunnel, and vice-versa.
All active SAs of a device are stored as SA data structures within a centralized database, known as a Security Assocation Database (SAD). Thus, each active SA, both inbound and outbound, has an entry in the SAD. When one device sends an IP packet that requires IPSec protection, the device transmitting the protected IP datagram will locate an appropriate SA entry in the SAD, update the SAD entry, and process, e.g., encrypt and/or authenticate, the packet in accordance with the SA located in the SAD entry. The encrypted packet is then transmitted to the non-secure network, via, for example, a network processor. Likewise, when a device receives a protected IP datagram, the receiving device locates an appropriate SA entry in the SAD, processes the packet in accordance with the SA located in the SAD entry, and updates the SAD entry.
Secure data transmission and processing is targeting higher and higher speeds. Thus, devices are being implemented that consist of multiple processing channels, each of which can process multiple packets. Potentially, individual channels in these multi-channel systems may need to access the same SAD entry simultaneously. As just noted, SAD entry update is part of the IPSec processing that takes place during both inbound and outbound processing of IPSec datagrams. Hence, if two or more channels access the same SAD entry simultaneously, these same channels may attempt to update the same SAD entry simultaneously, or substantially simultaneously. If this occurs some of the SAD entry updates will be lost, which could result in a security breach. Although complex algorithms and devices are known in the art for resolving such coherency issues, these known methods and devices are complex, and adversely affect system performance.
Hence, there is a need in the art for an apparatus and method that addresses the above-noted deficiencies. Namely, an apparatus and method that resolves SAD entry update coherency issues without relying on complex algorithms or devices. There is additionally a need for an apparatus and method that resolves SAD entry update coherency issues without introducing significant delay to IPSec traffic.